JP5103882B2 - Heart rate detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To slim a sensing unit without reducing the detection sensitivity. <P>SOLUTION: The sensing unit 100 for detecting the heartbeat of a human body comprises a sound receiving member 101 to vibrate in response to the heartbeat of the human body; a reflection member 102 to vibrate with different vibration characteristics from the sound receiving member 101 in response to the vibration of the sound receiving member 101; and a spacer array 109 for retaining the shape of a cavity 105 formed between the sound receiving member 101 and the reflection member 102 so that the opposite faces of the members are not brought into contact with each other. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a sensing unit and a heartbeat detection device.

  Conventionally, for example, there has been a technique for estimating the driver's arousal level according to the reaction state of the driver's autonomic nervous system, and supporting safe driving of the vehicle according to the estimated driver's arousal level. The driver's arousal level can be estimated using, for example, the driver's heart rate and respiratory rate per unit time, which changes according to the reaction state of the driver's autonomic nervous system.

  In addition, conventionally, for example, by measuring fluctuations in the heartbeat cycle according to the respiratory cycle and blood pressure that change according to the reaction state of the driver's autonomic nervous system, the driver's drowsiness is predicted. There was technology. The heartbeat cycle can be measured, for example, according to the electrocardiogram detected via an electrode attached to the body of the person to be measured for the heartbeat period. In particular, when the person to be measured is a driver, There is a need for a measurement method that can measure the heartbeat cycle without hindering driving.

  Conventionally, as a technique to meet such a demand, for example, a diaphragm type microphone having a sound collection pad structure having two air layers (resonance chambers) is attached to a seat belt, and heart sounds transmitted to the diaphragm are transmitted to two air layers (resonance chambers). There is a technique related to a vehicle heart sound detector that is introduced into a microphone via a room and measures a heart rate using a heart sound introduced into the microphone (for example, see Patent Document 1 below).

  Also, conventionally, for example, an air bag having airtightness or a sealed air type sound sensor of a sealed cabinet is attached to a mounting belt or the like that wraps around a human or animal body, and the air pressure in the air bag or the sealed cabinet is omnidirectional There has been a technique related to a biological information collecting apparatus that measures biological information such as a heart rate by detecting with a microphone or a pressure sensor (see, for example, Patent Document 2 below).

  Conventionally, for example, pressure fluctuations of a working fluid filled in a thin pressure sensor attached to a seat belt of a vehicle are detected by the pressure sensor, and a heartbeat and a respiratory state are detected according to the detected pressure fluctuations. (See, for example, Patent Document 3 below.)

Japanese Utility Model Publication No. 6-42373 JP 2001-286448 A JP 2002-166744 A

  However, in the conventional technique described in Patent Document 1 described above, the sound collecting pad is in close contact with the human body and the heart sound is detected in a state where an air layer is maintained between the diaphragm and the human body. In this case, the sound collection pad is applied between the diaphragm and the human body, such as clothing, where the surface has irregularities, so there is an air layer between the planar diaphragm and the irregular region such as clothing. There is a problem that it is difficult to continue maintaining the detection sensitivity and the detection sensitivity is lowered. Moreover, in the conventional technique described in Patent Document 1 described above, there is a problem in that there is a limit to thinning because a sound collection pad having two air layers is used.

  Further, in the conventional techniques described in Patent Documents 1 and 2 described above, it is difficult to stably maintain the structure when the biological information collecting apparatus is thinned, for example, to be attached to a seat bell. There is a problem that it is difficult to maintain good detection sensitivity. Furthermore, in the techniques described in Patent Documents 1 and 2, it is more difficult to stably maintain the structure when the area for receiving the heart sound is increased in order to compensate for the sensitivity reduction accompanying the reduction in thickness. There is a problem that it is difficult to maintain good detection sensitivity.

  An object of the present invention is to provide a sensing unit and a heart rate detection device that can be reduced in thickness without degrading detection sensitivity in order to eliminate the above-described problems caused by the prior art.

  In order to solve the above-described problems and achieve the object, a sensing unit according to the present invention is disposed opposite to a first diaphragm that vibrates according to a heartbeat of a human body, the first diaphragm, and the first unit. The second diaphragm that vibrates with vibration characteristics different from that of the first diaphragm according to the vibration of the first diaphragm and the opposing surfaces of the first and second diaphragms are in non-contact with each other. And a shape maintaining member for maintaining the shape of the cavity formed between the first and second diaphragms.

  According to this invention, since the first diaphragm can be prevented from coming into contact with the second diaphragm, the sensing unit can be thinned without reducing the detection sensitivity. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  In the above invention, the shape maintaining member may be a spacer provided in the cavity.

  According to the present invention, since the first diaphragm can be prevented from coming into contact with the second diaphragm with a simple configuration, the sensing unit can be thinned without reducing the detection sensitivity. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  In the above invention, the spacer may be separated from the first diaphragm.

  According to the present invention, the first diaphragm can be prevented from coming into contact with the second diaphragm without hindering the vibration of the first diaphragm, so that the sensing unit can be made thin without reducing the detection sensitivity. Can be achieved. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  In the above invention, the shape maintaining member may be an uneven portion provided in a non-vibrating region that does not vibrate according to the heartbeat of the human body in the first diaphragm.

  According to the present invention, the first diaphragm can be prevented from coming into contact with the second diaphragm without hindering the vibration of the first diaphragm, so that the sensing unit can be made thin without reducing the detection sensitivity. Can be achieved. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  Further, in the above invention, the shape maintaining member may be a plate-like member that is formed of a material different from a material that forms the first diaphragm and is laminated on the second diaphragm. .

  According to the present invention, since the first diaphragm can be prevented from coming into contact with the second diaphragm with a simple configuration, the sensing unit can be thinned without reducing the detection sensitivity. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  Further, in the above invention, a detection means for detecting a pressure change in the cavity due to vibration of the gas in the cavity is provided, and the cavity and the detection means have an airway through which the gas flows between the cavity and the detection means. It is good also as being connected by.

  According to the present invention, for example, even when the detection means and the cavity are separated due to restrictions on the layout, the pressure change in the cavity can be detected. Can be made thinner. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  In the above invention, the opening diameter of the airway may be smaller on the detection means side than on the cavity side.

  According to this invention, since the transmission loss of the pressure change in the airway can be reduced, the thickness of the sensing unit can be reduced with a simple configuration without reducing the detection sensitivity. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  In the above invention, a plurality of the cavities may be provided with different sizes, and may be communicated with one detection means by the airway.

  According to the present invention, vibrations of a plurality of types of frequencies having different sizes can be detected with a simple configuration, so that the detection sensitivity can be improved and the sensing unit can be thinned. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  Further, in the above invention, the detection means may be a condenser microphone including a diaphragm that vibrates according to the vibration of the gas in the airway and is provided at a position not facing the first diaphragm. Good.

  According to the present invention, the pressure change in the entire cavity can be detected, so that the detection sensitivity can be improved and the sensing unit can be made thinner. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  In the above invention, the capacitor microphone may be provided in the same plane as the surface of the second diaphragm.

  According to the present invention, it is possible to detect the pressure change in the cavity without giving the gas transmitting the pressure change to the condenser microphone the directivity for causing the gas to circulate in a specific direction. The sensing unit can be reduced in thickness without being lowered. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  In addition, according to the present invention, the condenser microphone is embedded in the second diaphragm, and vibration applied to the condenser microphone from the outside can be reduced, so that the sensing unit can be reduced without lowering the detection sensitivity. Thinning can be achieved. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  In the above invention, the thickness of the second diaphragm may be larger than the thickness of the first diaphragm.

  According to this invention, since the second diaphragm is less likely to vibrate compared to the first diaphragm, it is easy to detect the pressure change in the cavity due to the vibration of the first diaphragm. The configuration can reduce the thickness of the sensing unit without reducing the detection sensitivity. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  In the above invention, the second diaphragm may be made of a material different from a material forming the first diaphragm.

  According to the present invention, the pressure change in the cavity due to the vibration of the first diaphragm is detected by making the second diaphragm less likely to vibrate than the first diaphragm without changing the configuration. Therefore, the sensing unit can be thinned with a simple configuration without lowering the detection sensitivity. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  Further, in the above invention, the elastic member that is formed of a material having a lower elastic modulus than the first diaphragm and covers a non-vibration region that does not vibrate according to the heartbeat of the human body in the first diaphragm from the outside. It is good also as providing.

  According to the present invention, it is possible to more easily detect the pressure change in the cavity due to the vibration of the first diaphragm by making the vibration other than the vibration of the first diaphragm according to the heartbeat of the human body less likely to occur. With a simple configuration, the sensing unit can be thinned without reducing the detection sensitivity. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  In addition, a heartbeat detection device according to the present invention includes a plurality of the sensing units described above, and the sensing units are arranged in an array and are relative to the adjacent sensing units while maintaining a certain arrangement order. It is characterized by being freely displaceable.

  According to the present invention, the detection accuracy can be improved by detecting heartbeats with a plurality of sensing units, and each sensing unit can be brought into close contact with the human body. It is possible to reduce the thickness of the heart rate detecting device including the sensing unit. As a result, the sensing unit according to the present invention and the heartbeat detecting device including the sensing unit can accurately detect the user's heartbeat without giving the user annoyance or discomfort to the sensing unit and the heartbeat detecting device. .

  According to the sensing unit and the heart rate detecting device of the present invention, there is an effect that the thickness can be reduced without reducing the detection sensitivity.

  Exemplary embodiments of a sensing unit and a heart rate detecting device according to the present invention will be explained below in detail with reference to the accompanying drawings.

(Embodiment 1)
FIG. 1 is a sectional view showing a sensing unit according to the first embodiment of the present invention. First, the sensing unit according to the first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the sensing unit 100 includes a sound receiving member 101, a reflecting member 102, and a side pillar member 103. Each of the members 101 to 103 in the sensing unit 100 has a thin plate-like or sheet-like outer shape.

  The members 101 to 103 in the sensing unit 100 are laminated in the order of the sound receiving member 101, the side pillar member 103, and the reflecting member 102. That is, in the sensing unit 100, the sound receiving member 101 and the reflecting member 102 are disposed to face each other with the side pillar member 103 interposed therebetween. The plate thickness of the sound receiving member 101 is smaller than the plate thickness of the reflecting member 102. In the embodiment, a first diaphragm is realized by the sound receiving member 101 and a second diaphragm is realized by the reflecting member 102.

  The sound receiving member 101 is formed using, for example, a glass epoxy material, HDPE (high density polyethylene), hard rubber, or the like. As the hard rubber forming the sound receiving member 101, a hard rubber containing no metal particles is suitable. The reflecting member 102 is formed using, for example, ABS (acrylonitrile butadiene styrene) resin, LDPE (low density polyethylene), hard rubber, or the like. As the hard rubber forming the reflecting member 102, a hard rubber containing metal particles is suitable.

  The reflection member 102 is made of a material different from the material forming the sound receiving member 101. The reflecting member 102 is made of, for example, a material having a smaller elastic coefficient than the material forming the sound receiving member 101. The reflecting member 102 is less likely to vibrate than the sound receiving member 101.

  The side pillar member 103 is provided with a through hole 104 that penetrates the side pillar member 103 in the thickness direction of the side pillar member 103. The side pillar member 103 has a frame shape that borders the outer shape of the side pillar member 103 by providing the through hole 104.

  As described above, in the sensing unit 100, the sound receiving member 101 and the reflecting member 102 are disposed to face each other with the side pillar member 103 interposed therebetween, and therefore, between the sound receiving member 101 and the reflecting member 102. A space (hereinafter referred to as “cavity”) 105 is formed in accordance with the thickness of the side pillar member 103 and the shape of the through hole 104. The cavity 105 is filled with a gas such as air, for example.

  The reflecting member 102 is provided with a recess 106 that is recessed from the end surface of the reflecting member 102 on the sound receiving member 101 side in a direction away from the sound receiving member 101. A condenser microphone 107 is provided in the recess 106. The condenser microphone 107 is supported by the reflecting member 102 in a state of being embedded in the recess 106. Although detailed illustration and description are omitted because it is a known technique, the capacitor microphone 107 includes a pair of electrodes, and one electrode of the pair of electrodes is a diaphragm (hereinafter referred to as “diaphragm”). It is equipped with the structure.

  In the condenser microphone 107, the diaphragm vibrates according to the vibration of the gas around the diaphragm. When the diaphragm vibrates, the distance between the pair of electrodes in the capacitor microphone 107 changes, and the capacitance formed between the pair of electrodes changes. When the diaphragm vibrates with a certain amount of charge accumulated between the pair of electrodes, the voltage between the pair of electrodes changes. The capacitor microphone 107 outputs a voltage change between the pair of electrodes as an electric signal. Although not shown, the sensing unit 100 includes a power source for applying a constant charge to the condenser microphone 107.

  In the sensing unit 100, a power source for supplying electric charge to the capacitor microphone 107 is not necessarily provided. For example, instead of the condenser microphone 107, an electret condenser microphone may be used. An electret condenser microphone uses a property of semipermanently retaining electric charge when a high electric field of a dielectric such as Teflon (registered trademark) is applied, and a thin film holding electric charge (hereinafter referred to as “electret”) is used as an electrode. The capacitor microphone 107 does not need to supply power to the element by being attached.

  The electret in the electret condenser microphone may be a front electret with the electret attached to the diaphragm side or a back electret attached to the fixed electrode side. On the side opposite to the cavity 105, a cable that outputs a signal corresponding to a voltage change in the capacitor microphone 107 is connected to the capacitor microphone 107.

  An airway 108 through which gas flows between the cavity 105 and the space in contact with the diaphragm is formed between the cavity 105 and the space in contact with the diaphragm in the facing direction of the sound receiving member 101 and the reflection member 102. ing. The vibration of air in the cavity 105 is transmitted to the diaphragm through the airway 108. The opening diameter of the airway 108 is smaller than the opening diameter of the cavity 105.

  In the sound receiving member 101, a region facing the cavity 105 is a region that vibrates according to the heartbeat of the human body (hereinafter referred to as “sound receiving region”). When a pressure change occurs outside the sensing unit 100, the sound receiving region is more likely to vibrate compared to a region other than the sound receiving region (hereinafter referred to as “non-vibrating region”).

  The reflecting member 102 is provided with a spacer array 109 as a shape maintaining mechanism that protrudes toward the sound receiving member 101 at a position facing the cavity 105. The spacer array 109 includes a plurality of spacer members 110 projecting toward the sound receiving member 101, and is formed by arranging the spacer members 110 in an array at equal intervals. The spacer member 110 can be formed in a column shape such as a cylinder, for example. The spacer member 110 may have a rib shape whose longitudinal direction is a direction orthogonal to the arrangement direction of the spacer members 110, for example.

  FIG. 2 is an explanatory diagram showing the heartbeat detecting device according to the first embodiment of the present invention. Next, the heartbeat detection device according to the first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 2, the heartbeat detecting device 200 according to the first embodiment of the present invention includes a plurality of sensing units 100 described above. In the heartbeat detecting device 200, the sensing units 100 are arranged in an array in a state where their directions are aligned.

  Although not shown, each sensing unit 100 is attached to a flexible sheet formed using, for example, a plastic material. The flexible sheet has flexibility that can be deformed in accordance with an applied external force. In the heartbeat detection device 200, each sensing unit 100 is attached to the flexible sheet in a state where the sensing units 100 are spaced apart from each other by a predetermined distance and arranged in an array.

  FIG. 3 is an explanatory diagram (part 1) of a usage pattern of the heartbeat detecting device 200. Next, a usage pattern of the heartbeat detecting device 200 will be described with reference to FIG. As shown in FIG. 3, the heartbeat detecting device 200 is used by being attached to a seat belt 301 of a vehicle, for example. The heart rate detecting device 200 is positioned between the human body of the user 302 (hereinafter simply referred to as “user”) and the seat belt 301 with the user 302 wearing the seat belt 301. 301 is attached.

  Here, the user 302 is a person who uses the seat belt 301 provided in the driver's seat of the vehicle to which the heartbeat detecting device 200 is attached, that is, the driver of the vehicle. The heartbeat detecting device 200 is attached to the seat belt 301 of the vehicle with the reflecting member 102 side of each sensing unit 100 facing the seat belt 301 and the sound receiving member 101 of each sensing unit 100 facing the human body. It has been.

  FIG. 4 is an explanatory diagram (part 2) of the usage pattern of the heartbeat detecting device 200. FIG. 4 shows a state of the heartbeat detecting device 200 in a state where the user 302 wears the seat belt 301. As shown in FIG. 4, the heart rate detection device 200 is configured so that each sensing unit 100 is in close contact with the trunk of the human body when the user 302 wears the seat belt 301. It is curved along the trunk of the human body.

  The heartbeat detection device 200 in the state shown in FIG. 4 detects the heartbeat along the trunk of the user 302 by bending the flexible sheet to which the sensing unit 100 is attached between the adjacent sensing units 100. The entire device 200 is curved. By attaching the heart rate detection device 200 to the seat belt 301 of the vehicle, the user 302 can wear the seat belt 301 as usual and simultaneously position the heart rate detection device 200 in a state where heart rate can be detected.

  In a state where the user 302 wears the seat belt 301, pressure caused by vibration due to heartbeat is applied to the sound receiving member of each sensing unit 100. When pressure is applied to the sound receiving member 101, the sound receiving member 101 is deformed according to the applied pressure. When the magnitude of the applied pressure changes intermittently like vibration, the sound receiving member 101 vibrates according to the intermittent change of the applied pressure.

  When the sound receiving member 101 vibrates, the pressure in the cavity 105 changes with time. The change with time of the pressure in the cavity 105 is transmitted to the reflecting member 102, for example. As described above, since the reflecting member 102 is less likely to vibrate than the sound receiving member 101, the reflecting member 102 vibrates with a smaller amplitude than the sound receiving member 101.

  The vibration of the air in the cavity 105 is transmitted to the diaphragm in the condenser microphone 107 via the airway 108. When the diaphragm vibrates in accordance with the vibration of air in the cavity 105, in the capacitor microphone 107, the interval between the electrodes including the diaphragm changes, and the capacitance formed between the electrodes changes. Since a certain charge is accumulated in the capacitor microphone 107 via the power supply, the voltage changes with a change in capacitance formed between the electrodes. The condenser microphone 107 outputs a signal corresponding to the voltage change.

  FIG. 5 is an explanatory diagram showing a signal processing circuit in the heartbeat detecting device 200. As shown in FIG. 5, the heartbeat detection device 200 includes a first-stage amplifier unit 510 connected to the condenser microphone 107 and a waveform shaping circuit 520 connected to the first-stage amplifier unit 510. The first-stage amplifier unit 510 loads the frequency characteristics of the band structure on the signal output from the capacitor microphone 107.

  The waveform shaping circuit 520 includes a high-pass filter 521, a low-pass filter 522, and an ACL (Automatic Level Control) circuit 523. Although not described because it is a known technique, the high-pass filter 521 is a filter having a property of passing only a signal having a frequency equal to or higher than a predetermined cutoff frequency and attenuating a signal having a frequency equal to or lower than the cutoff frequency. High-pass filter 521 in the first embodiment removes a body motion component of 20 Hz or less.

  Similarly, although the description is omitted because it is a known technique, the low-pass filter 522 is a filter that passes only a low frequency among filters having a function of blocking signals other than a specific frequency, and has a specific threshold value. A higher frequency signal is attenuated and cut off, and only a low frequency is passed as a signal. The low pass filter 522 in the first embodiment removes components of 40 Hz or higher. Similarly, the ACL circuit 523 amplifies the signal that has passed through the low-pass filter 522 to a desired amplitude, although the description is omitted because it is a known technique. The ACL circuit 523 amplifies the signal to an arbitrary amplitude set when the heartbeat detecting device 200 is manufactured, for example.

  The first stage amplifier unit 510 includes bypass capacitors C1 and C2. The bypass capacitor C1 is provided so as to bridge a resistor 511 provided between the power supply line (Vcc) and GND. The bypass capacitor C2 is provided so as to bridge a resistor 512 provided between the waveform shaping circuit 520 and GND.

  The bypass capacitors C1 and C2 reduce impedance noise on the same principle as the low-pass filter 522 described above. By adjusting the capacitance of the bypass capacitor C1, only a predetermined frequency signal can be obtained. By providing the bypass capacitors C1 and C2, in addition to the heartbeat, for example, even when the diaphragm vibrates due to a noise component such as an uttered voice or a body sound, the heartbeat component can be accurately detected.

  In this way, by adjusting the characteristics in terms of electrical circuits, body movements, etc., even when the target is a sound of a frequency belonging to a low frequency such as a heart sound that cannot be structurally used for phase adjustment. Therefore, it is possible to avoid low frequency vibration of several Hz or less and mixing of components of about 80 Hz or more such as audio signals, and avoid saturation of acoustic frequency characteristics.

  6 and 7 are explanatory views ((No. 1) and (No. 2)) illustrating the heart sound measurement result. Next, the operation of the bypass capacitor C1 will be described with reference to FIGS. FIG. 6 shows a heart sound measurement result measured using the heartbeat detecting device 200 that does not include the bypass capacitor C1 in the circuit shown in FIG. FIG. 7 shows a heart sound measurement result measured using the heartbeat detection device 200 of the first embodiment that includes the bypass capacitor C1.

  As shown in FIG. 6, the heartbeat detection device 200 that does not include the bypass capacitor C <b> 1 responds to all sounds generated during the measurement of heart sounds, such as vocal cord vibrations according to the uttered sounds made during the measurement of the heart sounds. A signal including vibration is output. On the other hand, as shown in FIG. 7, the heartbeat detection device 200 including the bypass capacitor C1 outputs a signal based only on heart sounds from which vibration components other than heart sounds such as vocal cord vibrations are removed.

  FIG. 8 is an explanatory diagram (part 3) illustrating the heart sound measurement result. Next, a heart sound measurement result when using a conventional heart beat detection device and a heart sound measurement result when using the heart beat detection device 200 of the first embodiment will be described with reference to FIG. FIG. 8 shows the result of heart sound measurement during speech. Reference numeral 810 in FIG. 8 indicates a waveform output from the first stage amplifier. Reference numeral 820 in FIG. 8 indicates a waveform output from the waveform shaping circuit 520.

  As shown in FIG. 8, the waveform output from the first-stage amplifier is unclear because the vocal cord vibration due to speech is superimposed in addition to the heartbeat vibration. On the other hand, the waveform output from the waveform shaping circuit 520 has the vocal cord vibration due to the utterance removed, and the waveform of the heartbeat vibration can be grasped clearly.

  FIG. 9 is an explanatory diagram (part 4) illustrating the heart sound measurement result. Next, the heart sound measurement result at the time of sigh is shown using FIG. Reference numeral 910 in FIG. 9 indicates a waveform after the bypass capacitor C1 has passed through the bridged circuit. Reference numeral 920 in FIG. 9 indicates a waveform after passing through the waveform shaping circuit 520. Reference numeral 930 in FIG. 9 indicates a waveform after the bypass capacitor C2 passes through the bridged circuit. Reference numeral 940 in FIG. 9 indicates a waveform after passing through the waveform shaping circuit 520.

  Although illustration is omitted, among the running noise mixed through the seat belt 301 and the like, the signal components in the pass band are adaptively correlated using a plurality of arrayed sensor signals to reduce noise. It is effective. By increasing the dynamic range, it is possible to achieve a configuration that does not saturate with the first stage amplifier. In this case, all signals can be digitally processed. The dynamic range is a numerical value that represents the reproducibility of the signal, and is a numerical value that represents the ratio between the minimum value and the maximum value in dB units. Further, among the traveling noise mixed through the seat belt 301 or the like, a transfer function may be obtained for a signal component in the passband and removed by calculation.

  As described above, according to the sensing unit 100 of Embodiment 1 and the heartbeat detecting device 200 using the sensing unit 100, the sound receiving member 101 is reflected by the reflecting member 102 by the spacer array 109 provided in the cavity 105. Can be prevented from touching. Accordingly, the sensing unit 100 and the heart rate detecting device 200 can be reduced in thickness without reducing the detection sensitivity.

  In addition, according to the sensing unit 100 and the heartbeat detecting device 200 using the sensing unit 100 according to the first embodiment, the sound receiving member 101 is the reflecting member 102 with a simple configuration in which the spacer array 109 is provided in the cavity 105. It is possible to reduce the thickness of the sensing unit 100 and the heart rate detecting device 200 without lowering the detection sensitivity and reducing the detection sensitivity.

  In addition, according to the sensing unit 100 and the heartbeat detecting device 200 using the sensing unit 100 according to the first embodiment, each spacer member 110 constituting the spacer array 109 is separated from the sound receiving member 101. The sound receiving member 101 can be prevented from contacting the reflecting member 102 without disturbing the vibration of the sound member 101. Accordingly, the sensing unit 100 and the heart rate detecting device 200 can be reduced in thickness without reducing the detection sensitivity.

  In addition, according to the sensing unit 100 of Embodiment 1 and the heartbeat detecting device 200 using the sensing unit 100, the cavity 105 and the condenser microphone 107 are communicated with each other through the airway 108. Even when the 105 and the condenser microphone 107 are separated from each other, the pressure change in the cavity 105 can be reliably detected by the condenser microphone 107. Accordingly, the sensing unit 100 and the heart rate detecting device 200 can be reduced in thickness without reducing the detection sensitivity.

  In addition, according to the sensing unit 100 and the heartbeat detecting device 200 using the sensing unit 100 of the first embodiment, the diaphragm in the condenser microphone 107 is provided at a position that does not face the sound receiving member 101. It is possible to detect a pressure change in the entire cavity 105, not a pressure change caused by vibration transmitted from a specific location in the sound member 101. As a result, the detection sensitivity can be improved, and the sensing unit 100 and the heart rate detecting device 200 can be made thinner.

  In addition, according to the sensing unit 100 and the heartbeat detecting device 200 using the sensing unit 100 according to the first embodiment, the thickness of the reflection member 102 is made larger than the thickness of the sound receiving member 101, thereby receiving sound. Since the reflection member 102 is less likely to vibrate compared to the member 101 and the pressure change in the cavity 105 due to the vibration of the sound receiving member 101 can be easily detected, the sound receiving member 101 can be configured with a simple configuration. Contact with the reflecting member 102 can be prevented. Accordingly, the sensing unit 100 and the heart rate detecting device 200 can be reduced in thickness without reducing the detection sensitivity.

  In addition, according to the sensing unit 100 and the heartbeat detecting device 200 using the sensing unit 100 according to the first embodiment, the reflection member 102 is formed of a material different from the material forming the sound receiving member 101, thereby receiving the sound. The reflection member 102 is less likely to vibrate compared to the sound member 101, and a simple configuration can easily detect a pressure change in the cavity 105 due to the vibration of the sound receiving member 101. Accordingly, the sensing unit 100 and the heart rate detecting device 200 can be reduced in thickness without reducing the detection sensitivity.

  In addition, according to the heartbeat detection device 200 of the first embodiment, a plurality of sensing units 100 are arranged in an array, and the sensing units 100 are adjacent to each other in a state where the sensing units 100 maintain a certain arrangement order. Since it is relatively displaceable, detection accuracy can be improved by detecting heartbeats with the plurality of sensing units 100 in a state where each sensing unit 100 is in close contact with the human body.

  Further, according to the sensing unit 100 of Embodiment 1 and the heartbeat detection device 200 using the sensing unit 100, a signal corresponding to the voltage change in the capacitor microphone 107 is output on the opposite side of the capacitor microphone 107 from the cavity 105. Therefore, it is possible to prevent a noise component from being superimposed on a signal output from the condenser microphone 107 due to the presence of the cable in the cavity 105.

  As described above, the heart rate detection device 200 using the sensing unit 100 and the sensing unit 100 according to the first embodiment does not give the user annoyance or discomfort to the sensing unit 100 and the heart rate detection device 200. Heartbeat can be detected with high accuracy.

  Note that the position of the condenser microphone 107 in the sensing unit 100 and the heart rate detection device 200 using the sensing unit 100 is not limited to the above-described position. FIG. 10 is an explanatory diagram illustrating a modified example of the heartbeat detecting device according to the first embodiment. Here, a modified example of the heartbeat detecting device of the first embodiment will be described with reference to FIG.

  As shown in FIG. 10, in the heartbeat detection device as a modified example, the position of the condenser microphone 107 in the sensing unit 100 is a position that does not contact the body surface of the user 302 such as the clothes of the user 302. ing. Further, in the heartbeat detecting device as a modification, the position of the condenser microphone 107 in the sensing unit 100 is set to a position that does not interfere with the seat belt 301.

  According to the heartbeat detecting device including the sensing unit 100 having the structure shown in FIG. 10, a noise component caused by a contact sound caused by contacting the body surface of the user 302 or the seat belt 301 is transmitted to the condenser microphone 107. Can be reduced. Thereby, the heartbeat of the user 302 can be detected with high accuracy.

  Moreover, in the heartbeat detection apparatus 200 of Embodiment 1, it is not restricted to the sensing unit 100 mentioned above, You may use the sensing unit provided with another structure. Although illustration is omitted, for example, as a modification, instead of the sensing unit 100 in the heartbeat detecting device 200 of the first embodiment, the side pillar member 103 is not provided, and the sound receiving member 101 and the reflecting member 102 are used. A sensing unit in which a cavity 105 is formed between the sound receiving member 101 and the reflecting member 102 may be used.

  By using such a sensing unit, the number of parts can be reduced, and the number of assembly steps of the heart rate detection device 200 using the sensing unit and the sensing unit can be reduced.

(Embodiment 2)
FIG. 11: is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 2 concerning this invention. Next, a heartbeat detecting device according to a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, a heartbeat detecting device 200 including the sensing unit 1100 shown in FIG. 11 will be described instead of the sensing unit 100 in the heartbeat detecting device 200 of the first embodiment described above. In the second embodiment, the same parts as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 11, the sensing unit 1100 in the heartbeat detecting device 200 of the second embodiment includes a spacer member 1101 instead of the spacer member 110 constituting the spacer array 109 shown in FIG. . The spacer member 1101 is provided on the reflecting member 102 and protrudes from the reflecting member 102 toward the sound receiving member 101.

  The spacer member 1101 protrudes from the reflecting member 102 toward the sound receiving member 101 at a substantially central position of the cavity 105. In the spacer member 1101, the end on the sound receiving member 101 side is separated from the sound receiving member 101. The spacer member 1101 has a columnar shape such as a cylinder that releases the periphery of the spacer member 1101 to the extent that the air in the cavity 105 can move.

  In the above-described sensing unit 1100, an external force is applied to the entire sensing unit 1100 or the sound receiving member 101 so that the sound receiving member 101 approaches the reflecting member 102. Even when the member 101 is deformed, the sound receiving member 101 comes into contact with the spacer member 1101 and contact with the reflecting member 102 is avoided.

  As described above, according to the sensing unit 1100 of Embodiment 2 and the heartbeat detection device 200 using the sensing unit 1100, the sound receiving member 101 is reflected by the reflecting member 102 by the spacer member 1101 provided in the cavity 105. Can be prevented from touching. Accordingly, the sensing unit 1100 and the heart rate detecting device 200 can be thinned without reducing the detection sensitivity.

  In addition, according to the sensing unit 1100 and the heartbeat detecting device 200 using the sensing unit 1100 according to the second embodiment, the sound receiving member 101 is the reflecting member 102 with a simple configuration in which the spacer member 1101 is provided in the cavity 105. It is possible to reduce the thickness of the sensing unit 1100 and the heart rate detecting device 200 without lowering the detection sensitivity and reducing the detection sensitivity.

  In addition, according to the sensing unit 1100 and the heartbeat detecting device 200 using the sensing unit 1100 of the second embodiment, since the spacer member 1101 is separated from the sound receiving member 101, the sound receiving member 101 is vibrated. It is possible to prevent the sound receiving member 101 from coming into contact with the reflecting member 102 without hindering. Accordingly, the sensing unit 1100 and the heart rate detecting device 200 can be thinned without reducing the detection sensitivity.

  As described above, the heart rate detecting device 200 using the sensing unit 1100 and the sensing unit 1100 according to the second embodiment does not give the user annoyance or discomfort to the sensing unit 1100 and the heart rate detecting device 200. Heartbeat can be detected with high accuracy.

(Embodiment 3)
FIG. 12 is a sectional view showing a sensing unit in the heartbeat detecting device according to the third embodiment of the present invention. Next, a heartbeat detecting device according to a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, a heartbeat detecting apparatus 200 including the sensing unit 1200 shown in FIG. 12 will be described instead of the sensing units 100 and 1100 in the heartbeat detecting apparatus 200 of the first and second embodiments described above. In the third embodiment, the same parts as those in the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 12, the sensing unit 1200 in the heartbeat detecting device 200 of the third embodiment includes an uneven portion 1201 in place of the spacer member 110 constituting the spacer array 109 shown in FIG. . The concavo-convex portion 1201 is provided on the outer surface of the sound receiving member 101 and has a plurality of grooves 1202 whose longitudinal direction is the direction intersecting the axial direction of the airway and rib-shaped grooves formed between the grooves 1202. And a protrusion.

  As shown in FIG. 12, in the sensing unit 1200, the capacitor microphone 107 is provided in the same plane as the end face of the reflecting member 102 on the cavity 105 side. Specifically, the capacitor microphone 107 is embedded in the reflecting member 102 so that the diaphragm is positioned in the same plane as the end surface of the reflecting member 102 on the cavity 105 side.

  When an external force is applied to the sensing unit 1200, the sensing unit 1200 has a force that acts to bend the sensing unit 1200 according to the external force and a repulsion that acts to maintain the shape against the external force. Power is generated. Since the sensing unit 1200 is provided with the uneven portion 1201, a bending force and a repulsive force are generated in a plurality of directions, respectively. As a result, the sound receiving member 101 is difficult to bend in the longitudinal direction of the groove 1202.

  Further, the groove 1202 has a longitudinal direction in a direction perpendicular to the arrangement direction of the sensing units 1200 in the heartbeat detecting device 200. Thereby, the bending of each sensing unit 1200 can be prevented without interfering with the bending of the heartbeat device over the entire heartbeat detection device 200 along the trunk of the human body.

  For example, when the diaphragm is provided at a position protruding from the reflecting member 102 so as to enter the inside of the cavity 105 from the end surface of the reflecting member 102 on the cavity 105 side, the condenser microphone 107 side via the airway 108 is provided. Of the gas that transmits the pressure change, only a part of the gas that circulates closer to the cavity 105 side than the end surface of the reflecting member 102 on the cavity 105 side is transmitted to the diaphragm.

  Further, for example, when the diaphragm is provided at a position retracted from the end surface of the reflecting member 102 in a direction farther from the cavity 105 than the end surface on the cavity 105 side of the reflecting member 102, the capacitor is connected via the airway 108. Of the gas that transmits the pressure change to the microphone 107 side, only a part of the gas that wraps around the retracted portion is transmitted to the diaphragm. Thus, in any case, only a part of the gas that satisfies the specific condition can transmit the pressure change in the cavity 105 to the diaphragm.

  On the other hand, according to sensing unit 1200 and heartbeat detecting apparatus 200 using sensing unit 1200 of the third embodiment, as described above, the diaphragm in condenser microphone 107 is the end face on the cavity 105 side of reflecting member 102. Therefore, the vibration in the cavity 105 can be transmitted to the diaphragm without giving special directivity to the vibration.

  In addition, according to sensing unit 1200 and heartbeat detection apparatus 200 using sensing unit 1200 according to Embodiment 3, uneven portion 1201 is provided in the non-vibrating region of sound receiving member 101, and therefore sound receiving member 101 is provided. It is possible to prevent the sound receiving member 101 from coming into contact with the reflecting member 102 without disturbing the vibration. Accordingly, the sensing unit 1200 and the heart rate detecting device 200 can be reduced in thickness without reducing the detection sensitivity.

  In addition, according to the sensing unit 1200 and the heartbeat detecting device 200 using the sensing unit 1200 of the third embodiment, the condenser microphone 107 is embedded in the reflecting member 102, and vibration applied to the condenser microphone 107 from outside is applied. Therefore, it is possible to reduce the thickness of the sensing unit 1200 and the heart rate detection device 200 without reducing the detection sensitivity.

  As described above, the heart rate detection device 200 using the sensing unit 1200 and the sensing unit 1200 according to Embodiment 3 does not give the user annoyance or discomfort to the sensing unit 1200 and the heart rate detection device 200. Heartbeat can be detected with high accuracy.

(Embodiment 4)
FIG. 13: is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 4 concerning this invention. Next, a sensing unit in the heartbeat detecting device according to the fourth embodiment will be described with reference to FIG. In the fourth embodiment, a heartbeat detecting apparatus 200 including the sensing unit 1300 shown in FIG. 13 will be described instead of the sensing units 100, 1100, and 1200 in the heartbeat detecting apparatus 200 of the first to third embodiments. In the fourth embodiment, the same parts as those in the first to third embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As illustrated in FIG. 13, the sensing unit 1300 in the heartbeat detection device 200 according to the fourth embodiment includes a concavo-convex portion 1301 instead of the concavo-convex portion 1201 illustrated in FIG. 12 described above. The concavo-convex portion 1301 is provided on the outer surface of the sound receiving member 101, a plurality of ribs 1302 whose longitudinal direction is a direction intersecting the axial direction of the airway, and grooves formed between the ribs 1302; It is constituted by.

  When an external force is applied to the sensing unit 1300, the sensing unit 1300 has a force that acts to bend the sensing unit 1300 according to the external force and a repulsion that acts to maintain the shape against the external force. Power is generated. Since the sensing unit 1300 is provided with the uneven portion 1301, a bending force and a repulsive force are generated in a plurality of directions, respectively. As a result, the sound receiving member 101 is difficult to bend in the longitudinal direction of the rib 1302.

  The rib 1302 has a longitudinal direction in a direction perpendicular to the arrangement direction of the sensing units 1300 in the heartbeat detecting device 200. Thereby, the bending of each sensing unit 1300 can be prevented without interfering with the bending of the heartbeat device over the whole heartbeat detection device 200 along the trunk of the human body.

  As described above, according to the heart rate detection device 200 using the sensing unit 1300 and the sensing unit 1300 of the fourth embodiment, since the uneven portion 1301 is provided in the non-vibration region of the sound receiving member 101, the sound receiving The sound receiving member 101 can be prevented from coming into contact with the reflecting member 102 without disturbing the vibration of the member 101. Accordingly, the sensing unit 1300 and the heart rate detecting device 200 can be reduced in thickness without reducing the detection sensitivity.

  In addition, according to heart rate detection apparatus 200 using sensing unit 1300 and sensing unit 1300 of the fourth embodiment, as described above, the diaphragm in condenser microphone 107 is flush with the end face on the cavity 105 side of reflecting member 102. Therefore, the vibration in the cavity 105 can be transmitted to the diaphragm without giving special directivity to the vibration.

  In addition, according to the sensing unit 1300 and the heartbeat detecting device 200 using the sensing unit 1300 according to the fourth embodiment, the condenser microphone 107 is embedded in the reflecting member 102, and vibration applied to the condenser microphone 107 from outside is applied. Therefore, it is possible to reduce the thickness of the sensing unit 1300 and the heart rate detection device 200 without reducing the detection sensitivity.

  As described above, the heart rate detecting device 200 using the sensing unit 1300 and the sensing unit 1300 according to the fourth embodiment does not give the user the annoyance and discomfort to the sensing unit 1300 and the heart rate detecting device 200. Heartbeat can be detected with high accuracy.

(Embodiment 5)
FIG. 14 is a sectional view showing a sensing unit in the heartbeat detecting device according to the fifth embodiment of the present invention. Next, a sensing unit in the heartbeat detecting device according to the fifth embodiment will be described with reference to FIG. In the fifth embodiment, the heart rate detecting apparatus 200 including the sensing unit 1400 shown in FIG. 14 will be described instead of the sensing units 100, 1100, 1200, and 1300 in the heart rate detecting apparatus 200 of the first to fourth embodiments described above. . In the fifth embodiment, the same parts as those of the first to fourth embodiments described above are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 14, the sensing unit 1400 in the heartbeat detecting device 200 of the fifth embodiment includes a back plate 1401 instead of the spacer member 110 constituting the spacer array 109 shown in FIG. . The back plate 1401 is made of a material that is harder and less likely to vibrate than the material forming the sound receiving member 101 and the reflecting member 102. Specifically, for example, when the sound receiving member 101 is made of a polymer material such as PTB or PPS and the reflecting member 102 is made of aluminum, a plate-like member made of stainless steel is used as the back plate. Can do.

  As described above, according to the heart rate detection apparatus 200 using the sensing unit 1400 and the sensing unit 1400 according to the fifth embodiment, the back plate 1401 is stacked on the reflecting member 102, and therefore, the sound reception is performed with a simple configuration. It can prevent that the member 101 for use contacts the member 102 for reflection. Accordingly, the sensing unit 1400 and the heart rate detecting device 200 can be reduced in thickness without reducing the detection sensitivity.

  As a result, the heart rate detection apparatus 200 using the sensing unit 1400 and the sensing unit 1400 according to the fifth embodiment does not give the user annoyance or discomfort to the sensing unit 1400 and the heart rate detection apparatus 200. Can be detected with high accuracy.

(Embodiment 6)
FIG. 15 is a sectional view showing a sensing unit in the heartbeat detecting device according to the sixth embodiment of the present invention. Next, a sensing unit in the heartbeat detecting device according to the sixth embodiment will be described with reference to FIG. The sixth embodiment relates to the heartbeat detecting device 200 including the sensing unit 1500 shown in FIG. 15 instead of the sensing units 100, 1100, 1200, 1300, and 1400 in the heartbeat detecting devices 200 of the first to fifth embodiments described above. explain. In the sixth embodiment, the same parts as those in the first to fifth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 15, the sensing unit 1500 in the heartbeat detecting device 200 of the sixth embodiment includes a sound receiving member 101, a reflecting member 102, a back plate 1401, and an impact buffering member 1501. In the sensing unit 1500, a cavity 105 is formed by the sound receiving member 101 and the reflecting member 102. Specifically, the sound receiving member 101 and the reflecting member 102 in the sensing unit 1500 have a box shape having an opening that opens in a direction facing each other, and the opening is opposed to each other. The cavity 105 is formed in the combined state.

  Reference numeral 1502 in FIG. 15 denotes a cable that outputs a signal corresponding to a voltage change in the capacitor microphone 107. The cable 1502 is connected to the capacitor microphone 107 on the opposite side of the capacitor microphone 107 from the cavity 105. The back plate 1401 is provided with a notch 1503 that avoids the cable 1502.

  The shock absorbing member 1501 is formed of a material having a lower elastic modulus than that of the sound receiving member 101, and is provided so as to cover a non-vibration region in the sound receiving member 101 that does not vibrate according to the heartbeat of the human body from the outside. ing. The shock absorbing member 1501 is made of an elastic material capable of attenuating vibration applied to the sensing unit 1500 from the outside of the sensing unit 1500.

  Specifically, for example, when the sound receiving member 101 is formed of a polymer material such as PTB or PPS, the reflecting member 102 is formed of aluminum, and the back plate 1401 is formed of stainless steel, silicon rubber is shock-absorbed. It can be used as the member 1501.

  Note that, regardless of the sensing unit 1500 according to the sixth embodiment, the connection position of the cable 1502 to the condenser microphone 107 is opposite to the cavity 105. As a result, a signal corresponding to a voltage change in the capacitor microphone 107 can be obtained without causing unnecessary vibration in the cavity 105.

  As described above, according to the heart rate detection apparatus 200 using the sensing unit 1500 and the sensing unit 1500 of the sixth embodiment, the non-vibrating region in the sound receiving member 101 is covered from the outside by the shock absorbing member 1501. Therefore, it is possible to more easily detect the pressure change in the cavity 105 due to the vibration of the sound receiving member 101 by making it difficult for vibration other than the vibration of the sound receiving member 101 according to the heartbeat of the user 302 to occur. Thus, the sensing unit 1500 and the heart rate detecting device 200 can be thinned with a simple configuration without reducing the detection sensitivity.

  As a result, the heart rate detection apparatus 200 using the sensing unit 1500 and the sensing unit 1500 according to the sixth embodiment does not give the user the annoyance and discomfort with respect to the sensing unit 1500 and the heart rate detection apparatus 200. Can be detected with high accuracy.

(Embodiment 7)
FIG. 16: is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 7 concerning this invention. Next, a heartbeat detecting device according to a seventh embodiment of the present invention will be described with reference to FIG. The seventh embodiment describes a heartbeat detecting device 200 including the following sensing units instead of the sensing units 100, 1100, 1200, 1300, 1400, 1500 in the heartbeat detecting devices 200 of the first to sixth embodiments described above. To do. In the seventh embodiment, the same parts as those in the first to sixth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 16, the sensing unit 1600 according to the seventh embodiment of the present invention includes a cavity 1601 instead of the cavity 105 shown in FIG. The cavity 1601 in the sensing unit 1600 has a quadrangular shape in a plane including the end surfaces of the sound receiving member 101 and the reflecting member 102.

  As described above, according to the heart rate detection device 200 using the sensing unit 1600 and the sensing unit 1600 of the seventh embodiment, the cavity 1601 has a quadrangular shape. In addition, the volume of the cavity 1601 can be enlarged in accordance with 102, and the pressure change in the cavity 1601 due to the vibration of the sound receiving member 101 can be detected over a wide range. Accordingly, the sensing unit 1600 and the heart rate detection device 200 can be thinned with a simple configuration without reducing the detection sensitivity.

  As a result, the heart rate detecting device 200 using the sensing unit 1600 and the sensing unit 1600 according to the seventh embodiment does not give the user annoyance or discomfort with respect to the sensing unit 1600 and the heart rate detecting device 200. Can be detected with high accuracy.

(Embodiment 8)
FIG. 17 is a sectional view showing a sensing unit in the heartbeat detecting device according to the eighth embodiment of the present invention. Next, a heartbeat detecting device according to an eighth embodiment of the present invention will be described with reference to FIG. In the eighth embodiment, instead of the sensing units 100, 1100, 1200, 1300, 1400, 1500, 1600 in the heartbeat detection devices 200 of the first to sixth embodiments described above, the heartbeat detection device 200 including the following sensing units. Will be described. In the eighth embodiment, the same parts as those in the first to seventh embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 17, the sensing unit 1700 according to the eighth embodiment of the present invention includes a cavity 1701 instead of the cavity 105 shown in FIG. The cavity 1701 in the sensing unit 1700 has a quadrangular shape along the shape of the sound receiving member 101 so as to open over the entire sound receiving member 101. The airway 108 is shorter than the airway 108 shown in FIG. 1 described above by the increase in the size of the cavity 1701.

  As described above, according to the heart rate detection apparatus 200 using the sensing unit 1700 and the sensing unit 1700 of the eighth embodiment, the cavity 1701 has a quadrangular shape. 102, the volume of the cavity 1701 can be enlarged, and the pressure change in the cavity 1701 due to the vibration of the sound receiving member 101 can be detected over a wide range. Accordingly, the sensing unit 1700 and the heart rate detecting device 200 can be thinned with a simple configuration without reducing the detection sensitivity.

  As a result, the heart rate detection device 200 using the sensing unit 1700 and the sensing unit 1700 according to the eighth embodiment does not give the user annoyance or discomfort with respect to the sensing unit 1700 and the heart rate detection device 200. Can be detected with high accuracy.

(Embodiment 9)
FIG. 18 is a sectional view showing a sensing unit in the heartbeat detecting device according to the ninth embodiment of the present invention. Next, a heartbeat detecting device according to a ninth embodiment of the present invention will be described with reference to FIG. In the ninth embodiment, heart rate detection including the following sensing units instead of the sensing units 100, 1100, 1200, 1300, 1400, 1500, 1600, and 1700 in the heart rate detection devices 200 of the first to eighth embodiments described above. The apparatus 200 will be described. In the ninth embodiment, the same parts as those in the above-described first to eighth embodiments are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 18, the sensing unit 1800 according to the ninth embodiment of the present invention includes an airway 1801 instead of the airway 108 shown in FIG. The opening diameter of the airway 1801 is smaller on the condenser microphone 107 than on the cavity 105 side. The vibration of the airway 1801 that transmits the pressure change in the cavity 105 to the condenser microphone 107 attenuates from the cavity 105 side toward the condenser microphone 107 side.

  As described above, according to the heartbeat detection device 200 using the sensing unit 1800 and the sensing unit 1800 of the ninth embodiment, the opening diameter of the airway 1801 is smaller on the condenser microphone 107 side than on the cavity 105 side. Therefore, the transmission loss of the pressure change in the airway 1801 can be reduced. Thus, the sensing unit 1800 and the heart rate detecting device 200 can be thinned with a simple configuration without reducing the detection sensitivity.

  As a result, the sensing unit 1800 of Embodiment 9 and the heartbeat detecting device 200 using the sensing unit 1800 do not give the user 302 the annoyance and discomfort to the sensing unit 1800 and the heartbeat detecting device 200. It is possible to accurately detect the heartbeat.

(Embodiment 10)
FIG. 19 is a sectional view showing a sensing unit in the heartbeat detecting device according to the tenth embodiment of the present invention. Next, a heartbeat detecting device according to a tenth embodiment of the present invention will be described with reference to FIG. The tenth embodiment includes the following sensing units instead of the sensing units 100, 1100, 1200, 1300, 1400, 1500, 1600, 1700, and 1800 in the heartbeat detecting devices 200 of the first to ninth embodiments described above. The heartbeat detection device 200 will be described. In the tenth embodiment, the same parts as those in the first to ninth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 19, the sensing unit 1900 according to the tenth embodiment of the present invention includes cavities 1901 and 1902 in addition to the cavity 105 shown in FIG. The size of the cavities 1901 and 1902 is smaller than the size of the cavity 105. The sizes of the cavities 1901 and 1902 may be different between the cavity 1901 and the cavity 1902.

  Each of the cavities 105, 1901, and 1902 communicates with the condenser microphone 107 through an airway 1903. One end of the airway 1903 communicates with the condenser microphone 107, and the other end branches in the middle and communicates with the cavities 105, 1901, and 1902. All pressure changes in the cavities 105, 1901, and 1902 are transmitted to the condenser microphone 107.

  As described above, according to heart rate detection apparatus 200 using sensing unit 1900 and sensing unit 1900 of the tenth embodiment, a plurality of cavities 105, 1901, and 1902 having different sizes communicate with condenser microphone 107 through one airway 1903. Therefore, vibrations of a plurality of types of frequencies having different sizes can be detected with a simple configuration. Thus, the sensing unit 1900 and the heart rate detecting device 200 can be thinned with a simple configuration without reducing the detection sensitivity.

  As a result, the sensing unit 1900 and the heartbeat detecting device 200 using the sensing unit 1900 according to the tenth embodiment do not give the user 302 annoyance and discomfort to the sensing unit 1900 and the heartbeat detecting device 200. It is possible to accurately detect the heartbeat.

(Embodiment 11)
FIG. 20 is a sectional view showing a sensing unit in the heartbeat detecting device according to the eleventh embodiment of the present invention. Next, a heartbeat detecting device according to an eleventh embodiment of the present invention will be described with reference to FIG. In the eleventh embodiment, instead of the sensing units 100, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900 in the heart rate detection device 200 of the above-described first to tenth embodiments, the following sensing units are used. A heartbeat detection device 200 including the above will be described. In the eleventh embodiment, the same parts as those in the first to tenth embodiments described above are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 20, the sensing unit 2000 according to the eleventh embodiment of the present invention is the same as the above-described unit 2010 formed by the cavity 105, the condenser microphone 107, and the airway 108 shown in FIG. Two are provided per one.

  The units 2010 are provided in alternate directions so that the condenser microphones 107 in each unit 2010 are separated from each other. The size of the cavity 105 in each unit 2010 may be different for each unit 2010.

  As described above, according to the heart rate detection apparatus 200 using the sensing unit 2000 and the sensing unit 2000 according to the eleventh embodiment, since the pressure change in each cavity 105 is detected using the plurality of units 2010, a simple configuration is provided. Thus, it is possible to detect the vibration of the frequency over a wide range. Accordingly, the sensing unit 2000 and the heart rate detecting device 200 can be thinned with a simple configuration without reducing the detection sensitivity.

  In addition, according to the sensing unit 2000 and the heartbeat detection device 200 using the sensing unit 2000 of the eleventh embodiment, when the size of the cavity 105 in each unit 2010 is different for each unit 2010, a plurality of types having different sizes are provided. It is possible to detect vibrations having a frequency of. Accordingly, the sensing unit 2000 and the heart rate detecting device 200 can be thinned with a simple configuration without reducing the detection sensitivity.

  As described above, the heart rate detection device 200 using the sensing unit 2000 and the sensing unit 2000 according to the eleventh embodiment does not give the user 302 a sense of inconvenience or discomfort with respect to the sensing unit 2000 and the heart rate detection device 200. 302 heartbeats can be detected with high accuracy.

(Appendix 1) a first diaphragm that vibrates according to the heartbeat of the human body;
A second diaphragm that is disposed opposite to the first diaphragm and vibrates with a vibration characteristic different from that of the first diaphragm according to the vibration of the first diaphragm;
A shape maintaining member that maintains the shape of the cavity formed between the first and second diaphragms such that the opposing surfaces of the first and second diaphragms are not in contact with each other;
A sensing unit comprising:

(Appendix 2) The shape maintaining member is
The sensing unit according to appendix 1, wherein the sensing unit is a spacer provided in the cavity.

(Appendix 3) The spacer is
The sensing unit according to appendix 2, wherein the sensing unit is separated from the first diaphragm.

(Appendix 4) The shape maintaining member is
The sensing unit according to appendix 1, wherein the first vibration plate is an uneven portion provided in a non-vibration region that does not vibrate according to the heartbeat of the human body.

(Appendix 5) The shape maintaining member is
The sensing unit according to appendix 1, wherein the sensing unit is a plate-like member formed of a material different from a material forming the first diaphragm and stacked on the second diaphragm.

(Additional remark 6) It is provided with the detection means which detects the pressure change in the said cavity accompanying the vibration of the gas in the said cavity,
The cavity and the detection means are:
The sensing unit according to any one of appendices 1 to 5, wherein the sensing unit is communicated by an airway through which gas flows between the cavity and the detection means.

  (Supplementary note 7) The sensing unit according to supplementary note 6, wherein an opening diameter of the airway is smaller on the detection means side than on the cavity side.

(Appendix 8) A plurality of the cavities are provided with different sizes.
The sensing unit according to appendix 6, wherein the sensing unit is communicated with one of the detection means by the airway.

(Supplementary note 9) The detection means includes:
The sensing unit according to appendix 6, wherein the sensing unit is a condenser microphone provided with a diaphragm that vibrates according to the vibration of the gas in the airway and is not directly opposed to the first diaphragm.

(Appendix 10) The condenser microphone is
The sensing unit according to appendix 9, wherein the sensing unit is provided in the same plane as the surface of the second diaphragm.

  (Supplementary note 11) The sensing unit according to any one of Supplementary notes 1 to 10, wherein a thickness of the second diaphragm is larger than a thickness of the first diaphragm.

(Supplementary Note 12) The second diaphragm is
The sensing unit according to appendix 11, wherein the sensing unit is made of a material different from a material forming the first diaphragm.

  (Additional remark 13) The elastic member which is formed with the material whose elastic modulus is lower than the said 1st diaphragm and covers the non-vibration area | region which does not vibrate according to the heartbeat of the said human body in the said 1st diaphragm from the outside is provided. The sensing unit according to any one of supplementary notes 1 to 12, characterized in that:

(Supplementary Note 14) A plurality of sensing units according to any one of Supplementary Notes 1 to 13 are provided,
Each of the sensing units is arranged in an array with a predetermined distance from the adjacent sensing units.

It is sectional drawing which shows the sensing unit of Embodiment 1 concerning this invention. It is explanatory drawing which shows the heartbeat detection apparatus of Embodiment 1 concerning this invention. It is explanatory drawing (the 1) which shows the usage condition of a heart rate detection apparatus. It is explanatory drawing (the 2) which shows the usage condition of a heart rate detection apparatus. It is explanatory drawing which shows the signal processing circuit in a heart rate detection apparatus. It is explanatory drawing (the 1) which illustrates a heart sound measurement result. It is explanatory drawing (the 2) which illustrates a heart sound measurement result. It is explanatory drawing (the 3) which illustrates a heart sound measurement result. It is explanatory drawing (the 4) which illustrates a heart sound measurement result. It is explanatory drawing which shows the modification of the heartbeat detection apparatus of Embodiment 1. It is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 2 concerning this invention. It is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 3 concerning this invention. It is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 4 concerning this invention. It is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 5 concerning this invention. It is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 6 concerning this invention. It is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 7 concerning this invention. It is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 8 concerning this invention. It is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 9 concerning this invention. It is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 10 concerning this invention. It is sectional drawing which shows the sensing unit in the heart rate detection apparatus of Embodiment 11 concerning this invention.

Explanation of symbols

100, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 190 Sensing unit 101 Sound receiving member 102 Reflecting member 105, 1601, 1901, 1902 Cavity 107 Condenser microphone 108, 1801, 1903 Airway 109 Spacer array DESCRIPTION OF SYMBOLS 110 Spacer member 200 Heart rate detection device 1101 Spacer 1201, 1301 Concavity and convexity 1401 Back plate

Claims (5)

A heartbeat detection device attached to a seat belt and used.
A first diaphragm that vibrates according to the heartbeat of the human body;
A second diaphragm that is disposed opposite to the first diaphragm and vibrates with a vibration characteristic different from that of the first diaphragm according to the vibration of the first diaphragm;
A shape maintaining member that maintains the shape of the cavity formed between the first and second diaphragms such that the opposing surfaces of the first and second diaphragms are not in contact with each other;
Equipped with multiple sensing units with
The sensing unit is attached to a flexible sheet in a state where the longitudinal direction of the seat belt and the longitudinal direction of the sensing unit are orthogonally arranged, and when the seat belt is worn, According to a shape, the heart rate detecting device is configured to be relatively displaceable with respect to the adjacent sensing units while maintaining a constant arrangement order. The shape maintaining member is
The heartbeat detection device according to claim 1, wherein the heartbeat detection device is a spacer provided in the cavity. The shape maintaining member is
The heartbeat detection device according to claim 1, wherein the first vibration plate is an uneven portion provided in a non-vibration region that does not vibrate according to the heartbeat of the human body. The shape maintaining member is
The heartbeat detecting device according to claim 1, wherein the heartbeat detecting device is a plate-like member formed of a material different from a material forming the first diaphragm and laminated on the second diaphragm. Detecting means for detecting a pressure change in the cavity due to gas vibration in the cavity;
The cavity and the detection means are:
The heartbeat detection device according to any one of claims 1 to 4, wherein the heartbeat detection device is communicated by an airway through which gas flows between the cavity and the detection means.

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